Answer
As left side transforms into right side, hence given identity-
$\frac{\tan A}{\sec A}$ = $\sin A$ is true.
Work Step by Step
Given identity is-
$\frac{\tan A}{\sec A}$ = $\sin A$
Taking L.S.
$\frac{\tan A}{\sec A}$
= $\frac{\sin A/\cos A}{1/\cos A}$
( Using reciprocal and ratio identities)
= $\frac{\sin A}{\cos A} . \frac{\cos A}{1}$
= $\sin A$ = R.S.
As left side transforms into right side, hence given identity-
$\frac{\tan A}{\sec A}$ = $\sin A$ is true.